import numpy as np
import pandas as pd
arr = np.arange(1,10).reshape(3,3)
df1 = pd.DataFrame(arr,columns=['a','b','c'])
df1.insert(0,'key',['001','003','002'])
print('第一个对象原始数据df1: \n',df1)
arr2 = np.arange(10,14).reshape(2,2)
df2 = pd.DataFrame(arr2,columns=['a','e'])
df2.insert(0,'key',['001','004'])
print('第二个对象原始数据df2: \n',df2)
df3 = pd.concat([df1,df2])
print('纵向外合并的数据df3: \n',df3)
df4 = pd.concat([df1,df2],keys=['df1','df2'],sort=True)
print('纵向外合并，标记每个对象，并按列标签排序的数据df4: \n',df4)
df5 = pd.concat([df1,df2],join='inner',ignore_index=True)
print('纵向内合并并重新设置连续行标签的数据df5: \n',df5)